1. Field of the Invention
The present invention relates to a liquid crystal display device to be equipped on the ceiling in the cabin of an airplane, which may be retracted when not in use.
2. Description of the Prior Art
Many types of display devices are used in the cabin of an airplane for displaying video images and the like, which include a CRT television, a projector for projecting images onto a screen, or a small liquid crystal display equipped on the passenger seats.
Since liquid crystal displays are light in weight compared to the CRT television, it is suited for use on the airplane. A large screen liquid crystal display which may be viewed from a plurality of passenger seats is also proposed.
For example, U.S. Pat. No. 5,096,271 discloses a retractable display device, and U.S. Pat. No. 5,467,106 discloses a retraction structure of the display.
Moreover, U.S. Pat. Nos. 5,583,735 and 5,743,487 also disclose similar retractable display devices.
The present invention aims at providing an improved liquid crystal display device to be equipped in the cabin of an airplane.
The liquid crystal display device according to the present invention comprises, as a basic composition, a housing, a cover surrounding the housing, a liquid crystal display mounted to the housing revolvably between a retracted position and an evolved position, a control unit of the liquid crystal display, a drive unit of the liquid crystal display, and a control unit of the drive unit, wherein a liquid crystal panel of the liquid crystal monitor is placed, at said retracted position, so as to oppose to the control unit of the liquid crystal display being fixed to the housing. Further, the drive unit of the liquid crystal display is equipped with a motor, a reduction gear for reducing the output of the motor, an intermediate shaft driven by the output of the reduction gear, two coil-springs arranged in parallel to the intermediate shaft, a main shaft connected through a gear to the intermediate shaft, an arm mounted on the main shaft, and a bracket for mounting a liquid crystal display supported revolvably by said arm.
The liquid crystal display device further comprises a sensor for detecting the revolution of the liquid crystal display against said supporting arm.
Moreover, the drive unit of the liquid crystal display is equipped with a motor, a first one-way clutch transmitting only the forward direction rotation of the motor, a clutch to which the output of the first one-way clutch is inputted, a reduction gear to which the output of the clutch is inputted, an intermediate shaft driven by the output of the reduction gear, two coil-springs arranged in parallel to the intermediate shaft, a main shaft driven by the intermediate shaft, and a liquid crystal display supported by the main shaft, and the liquid crystal display is driven from the retracted position to the evolved position by the driving force of said motor, and driven from the evolved position to the retracted position by the spring force of said coil-springs.
The liquid crystal display device further comprises a second one-way clutch to which the output of said clutch is inputted, and a brake to which the output of said second one-way clutch is inputted, wherein the brake generates a braking force when the power supply to the liquid crystal display device is stopped, and the second one-way clutch transmits the braking force to the movement of the liquid crystal display toward the evolving direction. The liquid crystal display device further comprises a device for releasing the operation of the brake manually.
Even further, the liquid crystal display device comprises a third one-way clutch to which the output of the clutch is inputted, and a damper to which the output of the third one-way clutch is inputted, wherein the third one-way clutch transmits the movement of the liquid crystal display toward the retracting direction to the damper.